Species description: The gametangial stage is a pink-red seaweed that grows to 30 cms long. It has erect, fluffy or densely tufted, spirally arranged branches that alternate. This gives the appearance of a cone-like or feather-like growth. Some branches have conspicuous barbed harpoon-like structures, which may be attached to other algae. The tetrasporic phase (=Falkenbergia) is of small fine filaments irregularly branched which aggregrate into small fluffy balls.

Habitat: Both phases are generally epiphytic and sublittoral or free floating. Usually found on the lower shore and shallow subtidal, in sheltered or moderately exposed areas.

Distribution: First recorded from Northern Ireland in 2012 on Rathlin Island as drift. Has since been recorded in Strangford Lough, Carlingford Lough and the outer Ards peninsula. It has been recorded the rest of Ireland, mostly in south and southwest, and there are records from most coasts of Britain aside from east to southeast coast.

Similar Species: Similar to some other red algae but the presence of harpoon-like structures should distinguish it from all others.

Key Identification Features:

• Fluffy or densely tufted branches appearing cone-like or feather-like.
• Branches alternate and are spirally arranged.
• Some branches have conspicuous barbed harpoon-like structures.

Distribution Map from NBN: Asparagopsis armata at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Asparagopsis armata at iNaturalist World Species Observations database.

WoRMS: Asparagopsis armata at World Register of Marine Species. Accepted name: Asparagopsis armata Harvey, 1855. AphiaID: 144438.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Bonnemaisoniales; Bonnemaisoniaceae; Asparagopsis